This application claims priority from Korean Patent Application No. 2004-69203 filed Aug. 31, 2004 and Korean Patent Application No. 2005-76591 filed Aug. 22, 2005, incorporated herein by reference in their entireties.
1. Field of the Invention
The present invention relates to a compressor applied to an air conditioner of a car, and more particularly, to a compressor which is provided with a single-headed piston, thereby reducing a pressure pulsation of a suction gas.
2. Background of the Related Art
In general, in a compressor applied to an air conditioner of a car, noise is generated due to a pressure pulsation of a suction gas or a discharge gas. At this time, particularly, the noise transferred to the inside of the car through an evaporator is transferred along a suction line, and so, it is necessary to reduce the pressure pulsation of the suction gas in order to reduce the noise transferred to the inside of the car.
In particular, a variable capacity type compressor generates much noise due to the pressure pulsation of the suction gas or discharge gas than a fixed capacity type compressor since the variable capacity type compressor is driven for a long time in a low flow state and a low lubrication state. So, the variable capacity type compressor needs a structure for reducing the noise.
In the conventional variable capacity type compressor applied to the air conditioner of the car, which has a single-headed piston, as the structure for reducing the pressure pulsation of the suction gas or discharge gas, for example, as shown in FIG. 1, suction and discharge muffler chambers 2 and 4 whose open portions are opposed to each other are respectively mounted on the outer circumferences of a cylinder block 1 and a rear housing 3, and edges of open ends of the muffler chambers 2 and 4 are sealed by a mutual bonding so as to secure a sufficient muffler space necessary for relieving the pressure pulsation of the suction gas or discharge gas without causing an increase of the overall length of the compressor.
Such conventional muffler structure prevents the increase of the overall length of the compressor, but it is unavoidable that the housing is expanded and the entire volume of the compressor is increased since the muffler space is formed on the outer circumference of the housing. With the above reason, the conventional muffler structure is improper as a muffler structure of a vehicle compressor which strictly requires a small size and a light weight.
To solve the above problem of the conventional compressor, Korean Patent Publication No. 2004-0021062 filed by the same applicant as the present invention discloses a compressor. Referring to FIG. 2, the prior art will be described only about parts contrasted with FIG. 1 in brief. As shown in the drawing, the compressor includes: a suction muffler chamber 11 formed on the outer circumference of a cylinder block 10 and having a suction port 12 communicating with the external refrigerant circuit; a discharge chamber 16 and a suction chamber formed inside a rear housing 15; and at least two suction passages 18 formed on the upstream portion of the suction chamber 17 for communicating the suction chamber 17 with the suction muffler chamber 11.
Furthermore, a valve plate 19 is interposed between the cylinder block 10 and the rear housing 15, and has at least one communicating hole 19a for communicating the suction passages 18 with the suction muffler chamber 11.
Refrigerant gas induced into the suction muffler chamber 11 through the suction port 12 from the external refrigerant circuit is sucked into the suction chamber 17 through the suction passages 18 formed in the rear housing 15. The sucked refrigerant gas is compressed according to operation of a single-headed piston 13 and a driving shaft 14, discharged to the discharge chamber 16 through a discharge hole 19b, and then, flown to the external refrigerant circuit through the discharge port 16a. 
Therefore, the compressor does not cause the increase of the overall length and the entire volume thereof, and can effectively reduce the pressure pulsation of the suction gas and the noise caused by the pressure pulsation.
However, the above conventional compressors do not have any structure for storing oil contained in suction gas, and so, have several problems in that lubrication of the whole compressor is deteriorated due to a lack of the oil at the time of an initial start after the compressor is turned off and a noise is generated due to the deterioration of the lubrication.
That is, if refrigerant inside the compressor is heated by external heat or stagnated for a predetermined time period when the compressor is turned off, the oil is separated from the refrigerant and collected in a part. By the above, the oil is insufficiently supplied to the suction chamber when the compressor is turned on, and so, the noise is generated due to friction of a valve and the valve plate.
Meanwhile, U.S. Pat. No. 5,062,773 discloses a swash plate type refrigerant compressor. In U.S. Pat. No. 5,062,773, a cylindrical separation chamber is formed in a suction passageway for separating oil from a refrigerant gas containing the oil and supplying the separated oil into a swash plate chamber, whereby a driving shaft and a member for supporting the driving shaft are lubricated.
However, in also the above structure, the swash plate type refrigerant compressor has the same problem as the above conventional compressors in that the oil is not supplied into the suction chamber so that the noise is generated due to friction of a valve and a valve plate.